The present invention relates to an air cleaner for removing air pollutants from an air stream, for instance such as the cleaning exhaust/intake gas of an amusement machine, said air cleaner comprising a filter device including at least one filter layer held by a filter holder in said airflow substantially perpendicular to a main flow direction thereof and including a plurality of preferably stick-shaped filter elements neighboring each other.
An air cleaner of the above mentioned type is known from WO 2007/028176 A1 disclosing a filter device for removing air polluting materials from machine exhaust. The device is provided with a plurality of filter sticks which are held at the opposite ends in a filter housing and arranged in a plurality of layers one above the other with a lateral offset. The said filter sticks are made of a porous material such as plastic foam which is wetted with a fluid such as silicone oil. Such wet filters are very effective in removing air polluting materials including ultrafine particles and gaseous pollutants such as unpleasant odors which are chemically absorbed and neutralized by coming into contact with the fluid. The array of the filter sticks is enclosed in a filter housing forming a tube-like channel in the cross-section of which the filter sticks are placed. This tube-like channel is intended to direct the flow of polluted air through the filter stick array and to prevent the airflow from getting out of the way of the filter sticks. However, such filter stick arrangement is disadvantageous in certain aspects, for example it has shown that there is no uniform filter load on all sticks, in particular the filter load onto the inner sticks is different from the filter load onto the outer sticks. Moreover, such filter stick arrangement is sensible to airflow velocity.
Another filter device having wet filter sticks for cleaning the exhaust air of office machines is known from EP 1 345 669 which suggests to hold the filter sticks in upright position at their opposite ends so that the fluid for wetting the elements is caused to flow downward along the filter sticks by gravity. The said fluid which is oil is stored in a compartment above the filter sticks, wherein an oil pad may be provided in said compartment.
Furthermore, EP 0 515 759 A1 discloses an air filter device provided with a cylindrical housing having its front and back faces covered with grilles so that the air to be cleaned can flow through said housing in which the filter body which may comprise carbon pellets is provided. The said filter housing is arranged at the back side of the motor of a ventilator directing airflow onto the open front face of said filter housing.
GB 28 984 discloses a device for washing smoke with a series of screens being placed in a flue through which the smoke flows. The screens are wetted wherein water coming from a supply tank flows down said screens.
GB 823 542 discloses an apparatus for cleaning combustion gases proceeding from a furnace forming part of a wood waste disposal plant wherein the gas is forced to flow through a channel in which a plurality of tubes is closely spaced from each other to urge the gas to flow through the gaps between the tubes. A scrubbing liquid for the gases flows down the outside of said tubes.